//*************** 简单继承  *****************/

class Point { }

class ColorPoint extends Point {

}

let cp = new ColorPoint(); // ReferenceError
cp instanceof ColorPoint // true
cp instanceof Point // true


//*************** super()  *****************/

class A {
    p() {
        return 2;
    }
}

class B extends A {
    constructor() {
        super();
        console.log(super.p()); // 2
    }
}

let b = new B();